Negatives: Less English in Isaan. Less western food. Far less nightlife. Less farangs to talk to. Less diverse culture.
Positives: The people are more friendly and genuine. Plenty of peaceful spots. Nobody tries hard to sell you things because you are farang so walking around is more relaxing. Cost of living is half Bangkok but probably the same as Pattaya. Cheap to hire a car. You can rent a 4wd under 1000 baht.